The present invention relates to an arrangement for cleaning the inner surfaces of a wool chamber for the manufacture of mineral wool.
In the manufacture of mineral wool, a melt of mineral raw material is caused into run to a fibrillation unit. This can consist of a series of rapidly rotating cylinders on which the melt runs down over the peripheral surfaces and is thrown out by these and stretched during the formation of fibres. A directed stream of gas deflects the fibres into a wool chamber and deposits them on a collecting means, which can consist of a perforated conveyor belt or one or more perforated drums.
Alternatively, the fibrillation unit can consist of a rapidly rotating centrifugal receptacle with a perforated peripheral surface. The melt runs down into the centrifugal receptacle and is thrown out through the holes and converted into fibre. A stream of gas deflects the fibres to the wool chamber and deposits them on the collecting means.
A thermosetting binder is added to the stream of fibres in the wool chamber so that the fibres fasten to each other to form a mat of mineral wool.
The addition of the binder is the cause of a troublesome problem. The binder deposits itself as small sticky drops on the fibres and wads of wool, with the consequence that the fibres and wads of wool which touch against the walls of the wool chamber easily fasten to the walls as a result of the adhesive action of the binder. The binder hardens rapidly in the hot environment in the wool chamber and the material fastened onto the walls forms a rapidly growing hard coating. This coating must be removed before it becomes too thick, which means that about once a week the machines must be stopped for the sheet-steel walls to be scraped clean. The cleaning is a difficult and time-consuming task.
Hitherto, attempts have been made to reduce or eliminate this problem by bolting onto the walls of the wool chamber a replaceable lining of mineral wool. When the surface is scraped clean, the lining board of mineral wool splits readily and its outer layer comes off together with the deposits. When the lining boards have been thereby reduced to a certain thickness, they must be replaced.
Linings consisting of polytetrafluoroethylene sheets attached to the walls of the wool chamber by screws, clamps and other fastening elements have also been used. The task of cleaning the walls of the wool chamber when using such sheets is easier than when the walls are made of uncoated sheet steel, but these plastic sheets too, must be replaced regularly by new ones.
It is also known for the walls of the wool chamber to be made movable, so that during their movement from one side of the chamber to the other they are cleaned while outside the region of the wool chamber.
According to the published EP Application No. 194,605, an attempt is made to overcome the deposit problem by water-cooling the walls of the wool chamber. Owing to the lower temperature of the walls, the drops of binder do not harden on contact with the walls, but, instead, come off and end up on the receiving conveyor.